Electronic devices use power to operate. Switched mode power converters are commonly used due to their high efficiency, small size and low weight to power many of today's electronics. Conventional wall sockets provide a high voltage alternating current (ac). In a switched mode power converter, a high voltage alternating current is converted to provide a well-regulated direct current (dc) output through an energy transfer element. The switched mode power converter includes a controller which provides output regulation by sensing one or more inputs representative of one or more output quantities and controlling the output in a closed loop. In operation, a power switch is utilized to provide the desired output by varying the duty cycle (typically the ratio of the on-time of the power switch to the total switching period), varying the switching frequency, or varying the number of pulses per unit time of the power switch in a switched mode power converter.
Integrated circuits are typically formed on a wafer. The wafer is then separated into individual die which contains one copy of the integrated circuit. The controller and the power switch may be integrated in the same die or may be in two separate dice.
Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the disclosed devices. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments disclosed.